Portal: Prelude RTX is a free mod for all Portal owners.

In partnership with NVIDIA and powered by RTX Remix, Portal: Prelude RTX is a remaster of the 2008 ModDB Mod of the Year Top 3 Winner, Portal: Prelude, with stunning full ray tracing and high-fidelity assets, the groundbreaking AI-accelerated performance of DLSS 3, and the lowest texture load times with RTX IO. Step into the boots of Abby, the newest testing associate in Aperture Science, as you solve nineteen mind-bending chambers putting your Portal skills to the ultimate test. Make use of momentum, perform narrow escapes through deadly particle fields, and learn to work with manipulated gravity while heartless but dedicated observers watch and berate your every move.

When you finally come face to face with the minds behind Aperture Science, witness the scientific hubris marking the downfall of the facility as the activation of GlaDOS sets the scene for the rest of the Portal series to follow.

Portal: Prelude RTX features

• Nineteen challenging new test chambers, many improved from the original mod's release.
  
• A total graphical overhaul of the game's lighting and assets, powered by RTX Remix in partnership with NVIDIA.
  
• A cast of several fully-voice acted characters compared to the robotic voices of the original.
  
• A dramatic origin story for one of the most iconic villains and settings in gaming.
  
• An experience created by modders, helmed by modders, and released for fans of Portal to test their mettle.